human factors

Aviation Maintenance 26-7
26.4 Human-Factors Actions and Interventions
This section provides additional detail on the entries in Table 26.4, showing human-factors considerations
in each project. System-level actions are treated first to provide additional system overview information.
For more details, see the review by Latorella & Prabhu (2000).
1. Socio-technical systems (STS) analysis. Within a complex system that is highly technical, laborintensive,
and highly regulated, there is still considerable room for alternative organizational designs,
and Taylor’s work in analysis of socio-technical systems in aviation maintenance (e.g., Taylor, 1990)
has been the foundation of organizational changes, as well as the maintenance resource management
(MRM) initiatives (see the following #2). Although individuals are usually highly motivated
and conscientious in their work, communication patterns between groups and between shifts are
often in need of improvement. The benefits of organizational changes that move decision-making
closer to the work point have already been demonstrated in improved aircraft availability and fleet
performance in a military context (Rogers, 1991).
2. Maintenance resource management training. The preceding STS analysis suggested the need for
improved communication procedures. Hence, an early project was undertaken to provide crew
resource management (CRM) training within the maintenance and inspection function on one
airline and measure its results (Taylor, 1993). CRM had already been applied successfully to reduce
crew coordination errors in flight crews (Heimreick, Foushee, Benson, & Russini, 1986). This
work extended into a whole series of MRM studies with regard to different airlines (e.g., Taylor,
2000). The studies showed the importance of interpersonal communication at all levels, particularly
by AMTs, who can be notoriously uncommunicative in their work. A complete book on
the importance of communication in aviation maintenance (Taylor & Christenson, 1998) has
been influential in the maintenance community, which detail many MRM programs and measure
their success in teaching and fostering effective communication. Similar programs have been
developed in Canada, for example, Dupont (1996) devised one based on prototypical error-prone
situations, and named it as Dupont “The Dirty Dozen.”
The MRM interventions noted earlier have all involved hangar-floor programs. These have
been used to train mechanics and other personnel to be aware of accident-prone situations, and
give them the communications skills (e.g., assertiveness) necessary to remedy adverse situations.
They have also been used to foster a “just culture” where root causes of incidents are the norm,
rather than laying blame on individuals (e.g., Reason & Hobbs, 2003). Other training programs
for maintenance have been devised by Walter (2000), based on task analysis, and by Endsley and
Robertson (2000) using situation-awareness concepts, particularly related to team functioning.
3. Hangar-floor human-factors programs. The change process in ergonomics typically involves
small groups of users and human-factors specialists performing analysis, redesign, and implementation
on the users’ own workplaces. At one airline partner, implementation was performed
using the analyses already carried out as part of the restrictive space project (see Access section),
which obtained good results. An existing methodology (Reynolds, Drury, & Broderick, 1994) was
adapted for use at that partner airline to provide a more systematic model using the audit program
(described earlier) for analysis, rather than the particular measures relevant to restrictive spaces.
4. Development of human-factors audit programs. The need for an ergonomics/human-factors
evaluation system has been apparent for some time, and audit programs have been developed
(e.g., Drury, 2001) to provide a rapid overview of the factors that are likely to impact human/
system mismatches at each workplace. In the aircraft inspection and maintenance context, there
is no fixed workplace, so that any audit program has to start with the workcard as the basic unit
rather than the workplace. Such a system was produced in conjunction with two airline partners
(Chervak & Drury, 1995; Lofgren & Drury, 1994) and tested for both large airliners and helicopters.
The system was tested for reliability and modified wherever needed, before being validated
against human-factors experts’ judgments; and significant agreement was found. The system can